Stabilizer for regulators



May 29, 1945. w E PRAY 2,377,300

STABILIZER FORY REGUIZIATORS Filed Aug. 14, 1942 mi, a

Patented May 29, 1945 UNITED STATES PATENT OFFICE STABILIZER FORREGULATORS Wilbur F. Pray, Dobbs Ferry, N. Y., assignor to AskaiiiaRegulator Company, Chicago, 111., a corporation of Illinois ApplicationAugust 14, 1942, Serial No. 454,856

6 Claims. (Cl. 121-41) This invention relates to stabilizers forregulators of the hydraulic or fluid jet type and, among other objects,aims to provide important improvements in compensating mechanism forsuch jet pipe relays. The idea is to minimize objectionable hunting dueto control impulses and to simplify the system by reducing friction andrendering it more stable. One of the principal aims is to provide in aregulator of the type employing a servo-motor and a stabilizer cylinder,a split fluid control circuit so that both the servomotor and stabilizerare actuated simultaneously by the operating fluid. Another aim is toprovide in a regulator of this type, a double jet pipe, movable as aunit, in which the operating hydraulic fluid is divided into two streamsto actuate the servo-motor and the stabilizer piston. Still another aimis to provide a regulator apparatus wherein the stabilizer cylinder ispreferably larger than the control cylinder and the rates of flow of theoperating fluid are so controlled as to obtain proportional movements ofthe stabilizer and the the servo-motor.

Other aims and advantages of the invention will appear in thespecification, when considered in connection with the accompanyingdrawing,

wherein the figure is a, diagrammatic illustration of one form ofapparatus embodying the invention.

The pipe or conduit 3, through which a fluid under pressure is flowing,is provided with a throttle valve 4 controlled by a piston 5 in acylinder 6. The pressure of the fluid is transmitted to a diaphragm I ina casing 8 by means of a pipe 8, the diaphragm being connected to a jetpipe ID by means of a rod II. The branch pipes |2 of the well known jetpipe relay I0, l2 are connected to opposite ends of the cylinder 6 bymeans of pipes I3 and H, the latter pipe having a throttle valve I5therein. This valve increases the overall stability of the control byincreasing the time of travel of the control valve 4 between its fullyopen and fully closed positions.

The force exerted by diaphragm I through the rod II on the jet pipe I0is counteracted by a compression spring l6 connected at one end to theopposite side of the jet pipe and at the other end to a micrometeradjusting device or screw Ill, the latter being mounted on one end of alever I8 pivoted at a fixed and appropriate intermediate point; IS. Theother end 2001! the lever is connected to a piston 2| mounted in astabilizing cylinder 22. A pipe 23 with a throttle or bypass valve 24intercommunicates the ends of the cylinder 22 and a pair of pipes 25 and28, the 66 .the piston 2|, after a certain length of time.

latter with a throttle valve 21, connect the ends of the cylinder 22with the branch pipes 28 forming with jet pipe 29 another jet piperelay. The valve 21 reduces the speed of the piston 2| to the right andexercises a stabilizing influence on the servo-motor of the secondrelay.

A compression spring in in a casing 3|, mounted on one end of thecylinder 22, acts in such a way that upon either right or left movementof the piston 2| the spring 30 is compressed to thereby urge the piston2| to its central or normal position in the cylinder 22.

The pipes Ill and 29 form a double jet pipe 32 integral or suitablyconnected together and pivotally mounted at an intermediate point 33. Apipe 34 supplies oil under pressure to the jet pipes l0 and 28.

The pressure in the conduit 3 is controlled by means of the throttlevalve 4 and the latter is controlled by the movement of the piston 5 inthe cylinder 6. An increase in pressure in the conduit 3 transmittedthrough the pipe 9 and to the diaphragm 1, moves the jet pipe Ill to theleft and thus throttles or closes the valve 4 as the hydraulic fluidfrom the jet pipe ||l enters the pipe |2, l3 and into cylinder 6, thevalve 4 closing until balance is obtained. As the jet pipe ||l moves tothe left, the opposite jet pipe 29 moves simultaneously to the right andthereby controls the operation of the piston 2| which, as the hydraulicfluid enters the pipes 28, 26 and in the cylinder 22 on the right sideof the piston 2|, compresses the spring 30, due to the movement of thepiston 2|. Movement of the piston 2| operates the lever I8 and changesthe compression of the spring IS. The spring pressure will be increasedwhen the piston 2| moves to the left, so that it will quickly restorethe jet pipe ID to its neutral position.

The adjustable by-pass valve 24, connecting both ends of the stabilizingcylinder 22, permits the spring 30, which has been placing the pistonunder tension, to return the latter to its middle or intermediateposition in its cylinder and thereby compensate for the originaldisplacement of In other words, the compensating cylinder constitutes adouble-acting dash-pot.

The two Jet pipes l0 and 23 move together or simultaneously in oppositedirections around a common pivot axis 33 through which the hydraulicfluid is supplied to both jet pipes from a common supply pipe 34. Also,the cylinders 6 and 22 are not in series but they are operated from thesame pilot 32 which latter is a double 2 2,s77,soo

t pipe or two oppositely directed jet pipes II or pipe 84, or which oneoperates the stabilizer pistonii andtheotherthecontrolpistonl. Thecontrol and stabilizer device has many advantages oi which a number arethe following: 1. The reset time can be controlled by the throttle valve24 without interfering with the throttling range or total controlledcondition change.

2. The throttling range is controlled by the fulcrum II and the openingin the valve 21.

3. By using sumcient volume of hydraulic fluid through jet pipe it. anyrelation of throttling rangetoresettimecanbesecured.

4. The adjustment of the throttling range and the reset time areindependent of the diameter and stroke of the control piston 5.

5. One standard stabilizer will take care of all requirements so that itshould always be D 8 ble to obtain proper adjustments in the fleld.

The operation oi the stabilizer will be obvious upon reference to U. 8.Patents Nos. 1,959,889 and 2,227,170, over which the present inventionis an improvement. The double Jet pipe is ad- Justed to its central orneutral position by means of the micrometer adjustment l1 and the needleor throttle valves ii, 24 and 21 are opened to provide for the desiredrate of control and to proportion the flows to the respective cylinders.It the control impulses imparted through the diaphragm I to the jet pipemove it in either direction from the neutral position, it will be seenthat the pistons I and II will be operated in opposite directions andthe stabilizing piston 2i will exert opposing force through thecompression spring II on the jet pipe to prevent over-shooting or bymanipulation oi the throttle or needle valves or the size oi the Jetpipe nozzles and the receiving oriflces.

The particular form or the double iet pipe and the mode of dividing thecontrol fluid into two streams may be varied without departing from thespirit of the invention. Any convenient arrangement of jet pipesoperating together to divide the fluid stream into separate circuitswill accomplish the results.

It will be understood by those skilled in the art that the termstabilizer" is used herein in the same sense as it is used in theaforesaid Patents Nos. 1,959,889 and 2,227,170. It is employed tominimise objectionable hunting of a regulator and tends to stabilize themovement or operation oi the control element or valve. It can properlybearestoringmeanaasappfledtoa tpipe.Itwillalsobeunderstoodthatthetermthrottling range," sometimes called"droop," represents theamountotchangeinthecontrolledpreasure betweendiflerent valve settings. It can be broadly stated that the greater thetime lag, the greater must be the throttling range, or total pressurevariation to avoid hunting.

Obviously, the present invention is not restricted to the particularembodiment thereof herein shown and described. Moreover, it is notindispensable that all the ieatures oi the invention be used conicintlv.since they may be employed advantageously in various combinations andsubcombinations.

What is claimed is:

i. In combination with a hydraulic regulator having a servo-motor and astabilizer, a movable jet Pi having two branches tor dividing theoperating fluid into two streams. one for actuating the servo-motor andthe other for simultaneously actuating the stabilizer, said stabilizerbeing connected to act on the jet pipe, and tending to restore it to itsneutral position. 1

2. In combination with a regulator 01' the hydraulic type having acontrolling servo-motor and a fluid operated; stabilizer, a plvotallymounted pipe having two nozzles supplied with operating fluid one nozzleconnected to actuate the control motor and the other nozzle to actuatethe stabilizer simultaneously, said stabilizer acting on the Jet pipe,and tending to restore it to its neutral position.

3. In combination with a regulator according to claim 2, in which theJet pipe is in the form of two oppositely directed nozzles supplied fromacommon fluid source.

4. In combination with a regulator according to claim 2, in which theservo-motor and the stabilizer are each provided with an operatingpiston of which the stabilizer piston is larger than the servo-motorpiston.

5. In combination with a regulator according to claim 2, in which theservo-motor and the stabilizer are each provided with an operatingpiston of which the stabilizer piston is larger than the servo-motorpiston, and in which control valves are provided to proportion the flowoi fluid to operate the pistons.

8. A regulator of the hydraulic type having two movable jet pipe nozzlessupplied with fluid from a common source, said regulator including aservo-motor operated by fluid delivered from one of said iet pipenozzles, and a stabilizer connected to be operated by fluid from theother or said jet pipe nozzles and acting on both 01' them to restorethem toneutral position.

WILBUR F. PRAY.

